Acid cells or batteries have a high percentage of carbon among their components. Those components can have various uses and there have been attempts to give a concrete use to disposable batteries that have completed their useful life. In previous art there have been numerous recycling processes for cells and batteries. For example, in document EP 0274059 of Jul. 27, 1988, titled “Process for recycling electric batteries, mounted printed circuit boards and electronic components” reveals a process for recycling electric batteries, mixtures of high power batteries for equipment having different chemical composition, as well as printed circuit boards and electronic components, by pyrolysis of the mixture which is carried out at a temperature between 450 and 650° C. Then the electrolysis of the pyrolysis residue is carried out, followed by the separation of the products of the electrolysis and the removal of the products accumulated on the electrodes. In this process, which is economically beneficial, residues that are non contaminating to the environment are generated and an initial selection of the material is not necessary.
Document WO 2005/101564, of Oct. 27, 2005, titled “ Procedure for recycling of a mixture of anode cells and batteries based on lithium”, refers to a procedure for the hydrometallurgical treatment of batteries that comprise at least an anode based on lithium, a salt dissolved in an electrolyte, and a cathode that comprises at least a metal and a combination of metals chosen among cobalt, nickel, manganese, and iron, with the objective of recovering the usable fractions, a procedure characterized because it comprises dry grinding at ambient temperature in an inert atmosphere, treatment by means of at least a magnetic separation and using a densiometric table followed by aqueous hydrolysis, with the objective of recovering at least the lithium in the form of lithium carbonate or phosphate, an anion of that electrolyte salt, and a concentrate based on at least one metal from that cathode.
None of the documents of the previous art reveals some kind of procedure for the specific recycling of the carbon contained in cells and batteries.
From what has been stated above, the present invention has the purpose of getting a carbon electrode from acid cells (CB) wastes with extremely high electrocatalytic activity that can be used as cathode or anode for various applications such as electrochemistry, electroplating, electrolytic refining, among others, some of its preferred applications being in the field of sensor electrodes.
The manufacture of carbon electrodes depends on the specific purposes of their application and on the origin of the raw material used. Because of the above, prior art also provides procedures for the manufacture of carbon electrodes. For example, document ES 8605050 of Mar. 16, 1986, titled “Manufacture of carbonaceous bodies, particularly carbon electrodes”, reveals a procedure for the production of carbonaceous bodies, in particular electrodes, with a parallelepiped, cubic or cylindrical shape for the electrolysis of aluminium by calcination of raw shaped bodies, which contain pyrolizable substances, in a tunnel furnace, in an oxiodizing atmosphere where the products of the distillation that are released by the binder are burnt completely. The carbonaceous bodies are produced from a mass of petroleum coke, anthracite, soot, graphite, or similar products added as binders, like coal-tar or tar. During the cooking of shaped bodies of this kind the binder is cooked, yielding desired mechanical and electric characteristics.
Document WO 2004/020365 of Mar. 11, 2004, titled “Process for the preparation of carbon electrodes”, describes a procedure for the preparation of carbon electrodes. This procedure comprises the following stages: (a) combination of a filling material, a coal-tar binder and carbon fibers derived from mesophase tar or PAN. Those fibers have a mean length between 4.23 mm and 82.55 mm (⅙ of an inch and 3.25 inches, respectively) to form an electrodestock in which the carbon fibers are present preferentially at a level of 0.5 to 10 parts by weight of the carbon fibers per 100 parts by weight of the filling material; (b) extrusion of the electrodestock to form green electrodestock; (c) cooking of the green electrodestock to form a charred electrodestock; (d) graphitization of the electrodestock by keeping the electrodestock charred at a temperature of at least 2,500° C. with the purpose of forming an electrode; and (e) selection of the amount of carbon fibers in relation to the filling material with the purpose of getting control of the electrode's longitudinal coefficient of thermal expansion (CET).
Document ES 0165308 of Apr. 16, 1944, titled “Procedure for obtaining carbon electrodes” reveals a procedure for obtaining carbon electrodes and the corresponding electrode dough starting from filling materials that contain carbon and the usual binders, which comprises adding to the binders, especially the soft tar, hydrochloric acid and/or chlorides that break up the hydrochloric acid when they react with the binder, to achieve improvements in the quality of gross briquettes and in the quality of the reheated electrode. In this way the number of cracks decreases and the working temperature interval increases. In this process the binders can be mixed with the additions that contain chlorine, adding them afterwards to the filling materials that contain carbon, or else the filling materials and the binders can be mixed first, in the usual manner, making preferentially, after mixing thoroughly, the additions that contain chlorine. None of the documents of the previous art reveals a procedure for obtaining carbon electrodes using as raw material carbon from acid cell (CB) wastes with extremely high electrocatalytic activity. The present invention has the objective of giving an appropriate use to the carbon contained in cells and batteries, for the manufacture of carbon electrodes, which can be used as cathodes or anodes in various applications such as in electrochemistry, electroplating, electrolytic refining, with one of their most interesting applications in the field of sensor electrodes.
For that purpose the present invention proposes a procedure that consists in extracting the carbon from the cell and then removing its covering, and then it must be boiled in distilled water and washed with boiling distilled water, and then with high purity neutral detergent until no more residues is obtained. The process also comprises sonicating in distilled water and subjecting the electrode to washing with petroleum ether or some other highly nonpolar solvent. Sonicating and washing with organic solvents from low to high polarity, reaching clean water, and then boiling the electrode in a solution containing a strong oxidant at an acid pH. These washing and sonicating steps can be repeated if necessary. Finally, the process comprises polishing in a conventional manner for its use. If desired, it can be inserted in teflon or PVC to insulate part of the surface. The electric connection can be made by forming an inner thread in the carbon.